Sources of renewable energies, in comparison with other sources of energy that are concentrated in limited number of countries, provide us with significant opportunities for economizing in consumption of energy in vast geographical areas, accompanied with energy security for the countries through leaning on interminable domestic sources, increasing of sustainability, reduction of air pollution and climate changes.
Population increase often results in excessive use of non-renewable energy resources, leading to increasing global warming and destruction of environmental masses. Many climatic changes in the coming 30 to 40 years may be influenced by current production of greenhouse gas and length of carbon dioxide's life time in Earth's atmosphere. It is one of the important objectives of many researchers around the world to move in the direction of meeting primary needs of human beings such as making the air warm or cool as well as achieving minimum level of using non-renewable energies.
Solar and wind energy are among the biggest and cheapest natural sources of energy. These huge sources of energy are capable of responding to a major part of human needs. Only 16.7% of the globally used energy comes from renewable energies and in the latter group, only 23% of it is from energies that depend on sun. This low percentage could be increased taking into account the complete availability of solar energy, its steadiness as well as its advantageous characteristics. On the other hand, proper ventilation and adjustment of the quality of internal air is an indispensable need for ensuring a healthy and comfortable life for human beings because 60% to 90% of our life time passes inside buildings. Hence, lack of proper ventilation and low or bad quality of internal air could result in respiratory diseases, allergy, asthma, etc., and it can directly impact the morale and work outcome of the residents.
One of the main disadvantages of the heating products using solar energy at the global level is that they use a unidimensional prospect and are not combined with other systems. Many of these systems only deal with heating of air while neglecting other aspects such as the light received by the internal space or an effective natural ventilation system or the view of the residents of the buildings.